Stabilized fuel oil compositions



2,696,427 Patented Dec. 7, 1954- STABILIZED FUEL OIL COMPOSITIONS Charles ..B.. Biswell,..Woodstown, N.- J.,-assignorto- E.- I: du Pont de;Nemours andsCompany, Wilmington, Del., a corporation of Delaware N r pl a o n y 6 951;- e No- 208,072

10 Claims... chu -63 This inventionrelates to fuel pil compositions s bilized;

a n t ripta i n', du ng stor e, id pa i r cracking andcatalytic" cracking 10f heavier 1 oils Until recently most fuel oils werqmade from vstraig'ht-run.dis

tillates, but it is now. appreciatedihat .theyw ifiliv' be obe tamed. more economicall I crude stocksg eral companies arenow'rnarketing blendscont-aining'lO to 60 percent catalytically cracked stocks-with straight-run fuels. From a cost and yield standpoint, it would be desirable to increase the proportion of catalytically cracked stock or to sell'catalytically cracked oil exclusively. However, this hasnotheretoforegbeen practicalbecause of a serious storage stability problem which is particularly acute w1th cat'alytically cracked oil Light fuel oils are'subj ect to deterioration during storage'and catalyticaly crackedfueloil-in particular-is very- Thedeterioration apparently is caused-by I the unstable.

mild but pr d iz ng.cond ion ex stin rin storage and I results in discoloration iofsthe. oil and inj-the formation of sludge or sedimenti whi ch gifgnotremoved plugs filter. screens,- orificesg and toth'er parts of-the equip ment used in burning the fuel, A

The high susceptibility to deteriorat ion,.of catalytically cracked fuel oils has made-, it necessary vto blendithern off With large proportions ,of. the less plentiful-but more stable straight-run stocks to meet the-min-imum-stabili-ty requirements... Nevertheless, many companies have experienced difiiculty with these fuelsand refiners are frequently forced to take backfrom the distributors offcolor oil gcontaining.considerable voil. insoluble residuezi,

Althoughjthe deteriorationof fuelyoilsiappearssto ine i volve oxidation, many of. theaantioxidants; usedt-imthe.

stabilization of gasoline,-..rubber and other organicycorm poundsrsubject to deteriorationunder the influence of oxygen are ineffective as stabilizers for fuel oil. The fol-- F lowing conventional gasoline antioxidants fail to inhibit; the deterioration of catalytic cracked fuel oil; N-n-bu tyl- N,N-di(sec-butyl) -p-phenylenediam ine,

. 1W0. compositions containing fuel oiljproduced'by." acatalytic hired States Patim fifiCe phenylmorpholine, N;N-diphenylethylenediamine,. p,p-

dimethoxydiphenylamine.

The object ofthis invention is to provide compositions containing fuel oil which are stabilized against rapid deterioration during storage withconsequent, discoloration and sludge formation.

Ihave found that compositions stabilized against de teriorationduring :storage may be: preparedby incur porating with 1 the fuel F oil 'a small amount offa :phenolici triamine having the .formula:

RI? im r in which: andz-Rzaare selectednfromrthe.group co n-v sistingwof; aliphatic. radicals containing tOI Q CaIbOD atoms. and idivalenti aliphaticiaradicals-iwhich'=.jointly:wit themitrogen :atomforma:heterocyclic:ring, and: R3 and R4 are-selected from the groupiconsisting' of hydrogen; methyl andiethyl;

Representatives members-\ of this? class ofr compounds: which are; effectiveifuel oil stabilizers are:

2,4,6- tri (dimethylaminomethyl). phenol 2,4,6-tri (pip eridinomethy1 phenol.

by thelcatalytic;cnackingrgofu 2,4,6;tr1(pyrrohdmomethyl) phenol,

For thisreason catalytic crackingijis the method most generallyused to *obtainioil =WithiWhiChl'I0 satlsfy the lncreasingdemand for distillate. fuel oils. v Soy-- 2,4,6 :tri(dimethylaminomethyl) 3.-me th.yl phenol 2,4,6-tri dimethylaminomethyl )Y-3Teth'yl, phenol 2' 2,4,6-tri. dimethylaminomethyl):3, 5?dimethyl 5 phenol Other typical compounds of this class are thoseimwhich'r. the phenol is substituted in the s2,.. 4 .and 6 positions with diethylaminomethyl, methyle'thylaminomethyl, diethanolaminomethyh. piperazinomethyl,- morpholinomethyl or pyrrolo'methyl radicals:

Compounds? 10f this sort maybe preparewbyvreactingy one moleof phenol with atleast: tliree mole"equivalents 1 each Lof hformaldeh-yde: and a'-seconda ry -"amine, as -de'- scrgibed by Bruson'and MacMtfllen, J."A'.'=C..S; 63, 2-70 (1 4-1).

I have also fo und rthat the phenolic triamine stabilizers are particularly effective when used inconjunction with small. amounts of metal deactivators of the o-hydroxyaralkylidene, aliphatic amine type, and particularly the o-hydroxybenzal aliphatic amines. A useful group of deactivatorsfor this purpose is. the N,N-di(o hydroxy;-' aralkylidene) alkylenediamines in which the amino groups are attached to different carbon atoms in the alkylenegroup, as for example, thecompound N;N-di(o -hydroxy-, benzal -1,2-diarninoprop ane... Deactivator. compounds of. this sort may be prepared by the condensation ofaliphatic amines with o-hydroxy aromatic aldehydes orketones. Other compounds. falling within this class which may be used in conjunction with phenolic triamines in. the practice: of this invention are N,N'-di(o-hydroxy-3- methoxybenzal) ethylenediamine, N,N'-di(o-hydroxy-' benzal) decamethylenediamine N ,N'-di(o-hydroxybenzal) triethyl enetetrarnine, N,N'-di.(o -hydroxybenzal) eth-. ylenediamine and N;N'-di(o-hydroxybenzal) 1,3 diamino propane. Another deactivator which .is particularlyeffective in thisconnection is 'o-hydroxybenzalaminoguanidine oleate. Mixtures of two or more deactivatorsmay'be employed with the, phenolic triamine stabilizer.

The preferred concentration of. stabilizing agent in' the composition will vary somewhat depending on the characteristics of the particular fuel oil to be stabilized, and

also on the stabilizing agent or combination of agents to beused; In general additions of from 0.0005 to 0.05 percent by weightof the triamine or of the mixture of triamine-and deactivator effectively inhibit the deteriora-- tionof the fuel oil, while concentrations of from 0.001 to 0.01 percent represent the preferred range. Smaller" amounts of stabilizers usually providean insufficient de.-' gree of inhibition, while greater amounts are needlessly wasteful of the stabilizingagent'.'

When a metal deactivator isemployed, it maybe mixed with the triamine and the mixture added to the fuel oil,-v or the two ingredients may beadded separately. In most cases the mixture should contain a major amountof the triamine and'a minor-amountof the deactivator. A preferred composition contains nine parts by weight of the triamine to'one' part of the deactivator, althoughmije tures containing from 50 to 95 parts by weight of' triamine with to 50 parts of the deactivator are effective. Although the metal deactivator serves to suppress the catalytic effect of copper in promoting the oxidation of fuel oil, this does not appear to be its only function, as even where no copper is present the mixture of triamine and deactivator shows advantages.

The effect of these various agents in preventing the deterioration of fuel oil is measured by an accelerated stability test. In this test 50 ml. of the oil to be tested are charged into a glass container and the container is placed in a suitable bomb and subjected to a pressure of 100 lbs. of oxygen at 210-212 F. for ten hours. The bomb is cooled and the oil is filtered at room temperature by gravity through No. 5 filter paper. The glass liner and filter paper are washed with naphtha. The amount of soluble residue in the filtrate is then determined by steam jet evaporation. The insoluble residue formed during the period of oxidation is dissolved from the liner and filter paper with a 50-50 mixture of acetone and methanol and is determined by air jet evaporation of the solution according to ASTM method D5 25-46. Both the soluble and the insoluble residue are expressed as milligrams per 100 ml. of fuel. A value for the insoluble residue of at least 3 milligrams per 100 ml. and sometimes appreciably higher appears to be acceptable to the trade. Soluble residue is somewhat less objectionable, although this depends somewhat on the way in which the fuel is burned. Furthermore the oil soluble residue may on further standing under oxidizing conditions become insoluble.

The following examples are illustrative of the improvement in stability which is obtained through the practice of this invention.

Example 1 Samples of freshly manufactured fuel oil No. 2 cracked by means of a fluid catalyst are inhibited with 0.005 percent by weight of various phenolic triamines and mixtures of triamines and metal deactivators. The inhibited oil samples are subjected to the stability tests described above, with the following results:

Residue, mg./l00 mls.

Stabilizing Agent Soluble Insoluble Example 2.

Samples of the same No. 2 fuel oil cracked with a fluid catalyst are treated with 0.005 percent of various phenolic triamines and mixtures of triamines and deactivators as in Example 1 and clean copper metal wire is added to each to catalyze its oxidation. The results on these samples obtained in the accelerated stability test previously described are shown in the following table.

Residue, mgJlOO mls.

Stabilizing Agent Soluble Insoluble None 91 12 0.005% 2,4,(i-tri(dlmethylarnluomethyl) phenol. 43 1. 2 0.005% 2,4,6-tri(piperidinomethyl) phenol 62 1. 0.005% 2,4,6-tri(di methylaminomet h y l) 3- mcthyl phenol 57 5. 3 0.005% 2,4,6-tri(dimethylaminomethyl)-3,5-

dimethyl phenol 67 0.004% 2,4,6 tri(dimethylamin0methy1) phenol; 0.t00l% o-hydroxybenzalaminoguanidine olea e Example 3 Samples of a different catalytically cracked fuel oil than is used in the preceding examples are treated with 4 stabilizing agents and tested by the accelerated stability test, both with and without the addition of copper wire as oxidaion catalyst. The results are as follows:

These results indicate that the phenolic triamine and the o-hydroxyalkylideneamine exert a synergistic effect when used in conjunction with one another.

Example 4 Samples of a catalytically cracked fuel oil having an API gravity at 60 F. of 22.4 and a distillation range from 424 to 638 F. are inhibited with mixtures of 2,4,6-tri(dimethylaminomethyl) phenol and a metal deactivator. The samples of inhibited oil are then subjected to the accelerated stability test previously described. The samples are tested both with and without copper wire catalyst and the quantities of soluble and insoluble gummy residue are determined. The results of the test are as follows:

Residue.1 ing/100 m s. Stabilizing Agent Copper Soluble Insoluble without. 111 6. 8 w' h 87.3 8.5 0.005% 2,4,6-tri(dimethylaminowithout.. 44.]. 3.5 0 $E;ly1)2pll91t. (d1 th 1 i {with 53.6 5.3

,-n me yamnomeui i phenol; 000059;, di(o-hyg1' 0 gsgx jybelz lalg if amingfiirppane. w

. r1 1me y aminomefli l henoi; 0.001% di(o-hyi?; 0 ggg xyybeiz lalglf-damintgarppane. W1

ri imet y amino- Inetl yl) phenol; 0.002% di(o-hy- Ffig 0 gggybelial)lflfiigminorgopane. w

. ,fi-tri imet yaminometl yl) phenol; 0.001% O-hydrobenzalaminoguenidine oleate. w

Example 5 Samples of a catalytically cracked fuel oil having an API gravity of 22.2 at 60 F. and a distillation range of 437 to 640 F. are inhibited with various amounts of a mixture consisting of 10 percent by weight of di(ohydroxybenzal) l,2-aminopropane and 90 percent by weight of 2,4,6-tri(dimethylaminomethyl) phenol. The samples are subjected to the same accelerated stability test as previously described. Tests are made both with and11 'without copper metal catalyst with the following res ts:

Residue, ing/ mls.

Wt. Percent of Inhibitor Copper Soluble Insoluble without-.. 119. 9 17. 9 wa l n 15. 3 W1 ou l1. 6 Q0005 with 106.6 12. 7 {without 87. 4 8. 6 with 103. 1 l2. 8 without... 39. 8 3. 1 wigguyu 51.3 4.0 wt ou 36.2 2.4 {with 40.1 2.6

wide range of concentration.

water.

of this deactivator.. and. 2.,4,6:tri(dimethylaminomethyl) phenol. catalyst.

The. samples. were subjected to, an accelerated; storage.

Tests were made with, andwithout added copper:

testtiniventedglass.bottles.atllQf F. for ten weeksx Tent.

weeks accelerated storage at 110? F. is believed to pro duce approximately the-same amount of deterioration in fuel oils as will result'from storageffor Oneyeanunder the normal conditions encountered in the field. At the end of the accelerated storage period the samples are compared in color using the ASTM NPA method. In this method the scale of grading is described as follows:

1 lily white 1%. cream white 2 extra pale 2 /2 extra lemon pale 3 lemon pale 3 /2 extra orange pale 4 orange pale 4 /2 pale 5 light red 6 dark red 7 claret red 8 opaque A grading of 3 is intended to represent a color falling between 2 /2 and 3 on the scale. It will be seen that by this test the smaller the number the better the color of the oil. The test results are as follows:

These data show that very considerable improvement in color and in both soluble and insoluble residue is achieved by the use of the combination of stabilizing agents herein disclosed.

Example 7 Samples of a fuel oil No. 2 dfstillate prepared by cracking with a fluid catalyst are inhibited with 0.01 percent by weight of a number of conventional gasoline antioxidants and rubber oxidation inhibitors. These samples together with a control sample of the oil and a sample stabilized with 0.01 percent by weight of 2,4,6-tri(dimethylaminomethyl) phenol are aged at 110 F. in vented glass bottles for ten weeks. The appearance of these samples after the storage period is summarized in the following table:

Agent Color Preeipitate None dark brown... heavy. 2,4,6-tri(dimethylaminomethyl) phenoL. light brown... slight.

N ,N -di(see-butyl)-p-phenylene diamine. very dark. eavy. N-(n-butyD-p-aminophenol .do Do. phenyl-alpha-naphthylamine d0 Do. p-hydroxyphenylmorpholine. do. very heavy. p,p-dimeth0xydiphenylamine do D0. 2,6-di(tert-butyl)-4-Iuethylphenol dark brown. heavy.

It will be seen from the above data that the only sample which was better than the control was the one containing a phenolic triamine.

I claim:

1. A stabilized hydrocarbon distillate fuel oil normally subject to discoloration and sludge formation due to the presence of cracked components, containing as an in- 6;. hibitor therefor from 0.00.05 to 0.05 percent $50K in which R and R2 are selected from the group consisting of methyl and ethyl radicals and divalent tetramethylene and pentamethylene radicals which jointly with the nitrogen atom form a heterocyclic ring, and R3 and R4 are selected from the group consisting of hydrogen, methyl and ethyl.

2. A stabilized hydrocarbon distillate fuel oil normally subject to discoloration and sludge formation due to the presence of cracked components, containing as an inhibitor therefor from 0.0005 to 0.05 percent by weight of 2,4,6-tri(dimethylaminomethyl) phenol.

3. A stabilized hydrocarbon distillate fuel oil normally subject to discoloration and sludge formation due to the presence of cracked components, containing as an inhibitor therefor from 0.001 to 0.01 percent by weight of 2,4,6-tri(dimethylaminomethyl) phenol.

4. A stabilized hydrocarbon distillate fuel oil normally subject to discoloration and sludge formation due to the presence of cracked components, containing as an inhibitor therefor from 0.0Ul to 0.01 percent by Weight of 2,4,6-tri(piperidinomethyl) phenol.

5. A stabilized hydrocarbon distillate fuel oil normally subject to discoloration and sludge formation due to the presence of cracked components, containing as an inhibitor therefor from 0.0005 to 0.05 percent by weight of a mixture of 50 to percent by weight of a phenolic triamine having the formula:

in which R1 and R2 are selected from the group consisting of methyl and ethyl radicals and divalent tetramethylene and pentamethylene radicals which jointly with the nitrogen atom form a heterocyclic ring, and R3 and R4 are selected from the group consisting of hydrogen, methyl and ethyl, and 5 to 50 percent by weight of an o-hydroxyaralkylidene aliphatic amine metal deactivator.

6. A stabilized hydrocarbon distillate fuel oil normally subject to discoloration and sludge formation due to the presence of cracked components, containing as an inhibitor therefor from 0.0005 to 0.05 percent by weight of a mixture of 50 to 95 percent by we.ght of 2,4,6-tri(dimethylaminomethyl) phenol and 5 to 50 percent by weight of an o-hydroxyaralkylidene alphatic amine metal deactivator.

7. A stabilized hydrocarbon distillate fuel oil normally subject to discoloration and sludge formation due to the presence of cracked components, containing as an inhibitor therefor from 0.0005 to 0.05 percent by weight of a mixture of 50 to 95 percent by weight of 2,4,6-tri(dimethylaminomethyl) phenol and 5 to 50 percent by weight of a N,N'-di(o-hydroxyaralkylidene) alkylenediamine metal deactivator in which the am.no groups are attached to dilferent carbon atoms in the alkylene group.

8. A stabilized hydrocarbon distillate fuel oil normally subject to discoloration and sludge formation due to the presence of cracked components, containing as an inh.bitor therefor from 0.001 to 0.01 percent by Weight of a mixture of 50 to 95 percent by weight of 2,4,6-tri(dimethylaminomethyl) phenol and 5 to 50 percent by weight of N,N-di(o-hydroxybenzal)1,2-diaminopropane.

9. A stabilized hydrocarbon distillate fuel oil normally subject to discoloration and sludge formation due to the presence of cracked components, containing as an inhibitor therefor from 0.001 to 0.01 percent by weight of a. mixture of 9 parts by weight of 2,4,6-tri(dimethylaminomethyl) phenol and 1 part by weight of N,Ndi(ohydroxybenzal) 1,2-diaminopropane.

10. A stabilized hydrocarbon distillate fuel oil normally subject to discoloration and sludge formation due to the presence of cracked components, containing as an inhibitor therefor from 0.001 to 0.01 percent by weight of a mixture of S0 to 95 percent by weight of 2,4,6-tri(dimethylaminomethyl) phenol and 5 to 50 percent by weight of o-hydroxybenzalaminoguanidine oleate.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,181,121 Downing et a1. Nov. 28, 1939 2,336,006 Fuller Dec. 17, 1943 2,363,134 McCleary Nov. 21,1944 2,369,490 Proell Feb. 13, 1945 2,422,566 Proell June 17, 1947 OTHER REFERENCES Bruson et al.: I. A. C. 5., vol. 63, 1941. 

1. A STABILIZED HYDROCARBON DISTILLATE FUEL OIL NORMALLY SUBJECT TO DISCOLORATION AND SLUDGE FORMATION DUE TO THE PRESENCE OF CRACKED COMPONENTS, CONTAINING AS AN INHIBITOR THEREFOR FROM 0.0005 TO 0.05 PERCENT BY WEIGHT OF A PHENOLIC TRIAMINE HAVING THE FORMULA: 